First Geothermal Plant in Alaska Starts Power Production

August 23, 2006

Chena Hot Springs announced on August 10th the successful
commissioning and startup of the first geothermal power plant in
Alaska. The unique 200-kilowatt power plant also holds a record for
producing power from the lowest temperature resource yet: a well
producing 162.5 degree Fahrenheit water. That's scalding hot water,
but far from boiling. To produce power from the well, the company
teamed with DOE, United Technologies, and Carrier Corporation to
fashion a binary power plant from commercial air-conditioning
equipment, using the air conditioning compressor as a turbine. The
system essentially runs in reverse: the geothermal heat vaporizes the
refrigerant; the refrigerant vapor passes through the compressor,
spinning it and a generator to produce power; and then a condenser
removes heat and converts the vapor back into a liquid. To make the
system more efficient, Chena Hot Springs pipes its cooling water in
from a well at a higher elevation, allowing gravity to push the water
through the power plant without a need to pump it. See Chena Hot Springs'
announcement,
power plant description, and technical paper on the power plant
(PDF 220 KB).
Download Adobe Reader.

Chena Hot Springs is a resort that makes the most of its renewable
resources, using the same gravity-fed water to irrigate its greenhouse
and gardens, and employing geothermal energy to heat its 46 buildings.
The resort is built around geothermal hot springs, but the company
also erected the Aurora Ice Hotel in January 2004 to showcase ice art.
When that structure melted during record temperatures in July 2004,
the resort built a new structure, the Aurora Ice Museum, and cooled it
with an absorption chiller that draws on geothermal energy. The new
structure, built in January 2005, survived more record-setting
temperatures that summer while hosting 10,000 visitors. The absorption
chiller won an award from the Geothermal Resources Council last year.
See the Chena Hot Springs Web site.